The changing behavior of the wireless channel causes fluctuations in the level of received signal power. In order to limit the effect of the varying wireless channel on system performance, a possible solution is to adopt reconfigurable antenna systems capable of adaptively tuning their radiation characteristics in response to the multivariate channel. Radiation pattern shape, polarization state and frequency of operation can be tuned to accommodate the operating requirements. Different solutions employing different techniques for reconfiguring the radiation characteristic have been proposed in the prior art.
Most of the proposed reconfigurable antennas achieve pattern and polarization reconfigurability by changing the current distribution on the antenna by means of RF switches embedded on the antennas, material changes or structural variations. Using these techniques allows generating different polarizations and radiation patterns but, especially when the antenna has several different configurations, it generally causes some of the antenna configurations to suffer of low gain or impedance mismatch. It is desired to overcome these issues and to achieve high gain pattern and polarization reconfigurable antennas that exhibit good impedance matching for all configurations. The present invention has been designed to address these and other needs in the art.